add option to force enable or disable bluetooth adapter

bramble-android/src/main/java/org/briarproject/bramble/plugin/droidtooth/DroidtoothPlugin.java

@@ -83,6 +83,7 @@ class DroidtoothPlugin implements DuplexPlugin, EventListener {
 
 	private volatile boolean running = false;
 	private volatile boolean wasEnabledByUs = false;
+	private volatile boolean forceEnabled = false;
 	private volatile BluetoothStateReceiver receiver = null;
 	private volatile BluetoothServerSocket socket = null;
 
@@ -154,7 +155,7 @@ class DroidtoothPlugin implements DuplexPlugin, EventListener {
 		} else {
 			// Enable Bluetooth if settings allow
 			if (callback.getSettings().getBoolean(PREF_BT_ENABLE, false)) {
-				enableAdapter();
+				enableAdapter(true);
 			} else {
 				LOG.info("Not enabling Bluetooth");
 			}
@@ -245,11 +246,12 @@ class DroidtoothPlugin implements DuplexPlugin, EventListener {
 		return new DroidtoothTransportConnection(this, s);
 	}
 
-	private void enableAdapter() {
+	private void enableAdapter(boolean force) {
 		if (adapter != null && !adapter.isEnabled()) {
 			if (adapter.enable()) {
 				LOG.info("Enabling Bluetooth");
 				wasEnabledByUs = true;
+				if(force) forceEnabled = true;
 			} else {
 				LOG.info("Could not enable Bluetooth");
 			}
@@ -261,11 +263,14 @@ class DroidtoothPlugin implements DuplexPlugin, EventListener {
 		running = false;
 		if (receiver != null) appContext.unregisterReceiver(receiver);
 		tryToClose(socket);
-		disableAdapter();
+		disableAdapter(true);
 	}
 
-	private void disableAdapter() {
-		if (adapter != null && adapter.isEnabled() && wasEnabledByUs) {
+	private void disableAdapter(boolean force) {
+		if (adapter != null && adapter.isEnabled() && wasEnabledByUs
+				&& (!forceEnabled || force)) {
+			if(force) forceEnabled = false;
+
 			if (adapter.disable()) LOG.info("Disabling Bluetooth");
 			else LOG.info("Could not disable Bluetooth");
 		}
@@ -431,26 +436,28 @@ class DroidtoothPlugin implements DuplexPlugin, EventListener {
 	@Override
 	public void eventOccurred(Event e) {
 		if (e instanceof EnableBluetoothEvent) {
-			enableAdapterAsync();
+			EnableBluetoothEvent enable = (EnableBluetoothEvent) e;
+			enableAdapterAsync(enable.isForced());
 		} else if (e instanceof DisableBluetoothEvent) {
-			disableAdapterAsync();
+			DisableBluetoothEvent disable = (DisableBluetoothEvent) e;
+			disableAdapterAsync(disable.isForced());
 		}
 	}
 
-	private void enableAdapterAsync() {
+	private void enableAdapterAsync(final boolean force) {
 		ioExecutor.execute(new Runnable() {
 			@Override
 			public void run() {
-				enableAdapter();
+				enableAdapter(force);
 			}
 		});
 	}
 
-	private void disableAdapterAsync() {
+	private void disableAdapterAsync(final boolean force) {
 		ioExecutor.execute(new Runnable() {
 			@Override
 			public void run() {
-				disableAdapter();
+				disableAdapter(force);
 			}
 		});
 	}

bramble-api/src/main/java/org/briarproject/bramble/api/plugin/event/BluetoothEvent.java

@@ -0,0 +1,20 @@
+package org.briarproject.bramble.api.plugin.event;
+
+import org.briarproject.bramble.api.event.Event;
+
+/**
+ * to force enable and disable bluetooth
+ * force enable means that the bluetooth adapter stay enabled until a force DisableBluetoothEvent is called
+ * force disable stop the bluetooth adapter only when we turned it on
+ */
+abstract class BluetoothEvent extends Event {
+	private boolean force;
+
+	BluetoothEvent(boolean force){
+		this.force = force;
+	}
+
+	public boolean isForced(){
+		return force;
+	}
+}

bramble-api/src/main/java/org/briarproject/bramble/api/plugin/event/DisableBluetoothEvent.java

@@ -11,5 +11,12 @@ import javax.annotation.concurrent.Immutable;
  */
 @Immutable
 @NotNullByDefault
-public class DisableBluetoothEvent extends Event {
+public class DisableBluetoothEvent extends BluetoothEvent {
+	public DisableBluetoothEvent(){
+		super(false);
+	}
+
+	public DisableBluetoothEvent(boolean force) {
+		super(force);
+	}
 }

bramble-api/src/main/java/org/briarproject/bramble/api/plugin/event/EnableBluetoothEvent.java

@@ -10,5 +10,12 @@ import javax.annotation.concurrent.Immutable;
  */
 @Immutable
 @NotNullByDefault
-public class EnableBluetoothEvent extends Event {
+public class EnableBluetoothEvent extends BluetoothEvent {
+	public EnableBluetoothEvent(){
+		super(false);
+	}
+
+	public EnableBluetoothEvent(boolean force){
+		super(force);
+	}
 }

briar-android/src/main/java/org/briarproject/briar/android/settings/SettingsFragment.java

@@ -326,8 +326,8 @@ public class SettingsFragment extends PreferenceFragmentCompat
 	}
 
 	private void enableOrDisableBluetooth(boolean enable) {
-		if (enable) eventBus.broadcast(new EnableBluetoothEvent());
-		else eventBus.broadcast(new DisableBluetoothEvent());
+		if (enable) eventBus.broadcast(new EnableBluetoothEvent(true));
+		else eventBus.broadcast(new DisableBluetoothEvent(true));
 	}
 
 	private void storeTorSettings(final int torSetting) {